Rotary damper

ABSTRACT

Disclosed is a rotary damper comprising a damper body mounted on a rotary shaft, a cam mechanism provided in the damper body to set a rotation pattern of the rotary shaft, a restoring force accumulating member which accumulates a restoring force in accordance with rotation of the rotary shaft, and a rotation control member for controlling the rotation of the rotary shaft, wherein the damper body is formed by setting a bottomed, cylindrical outer case having an opening at one end thereof and a bottomed, cylindrical inner case having an opening at one end thereof face to face with each other and fitting the two with each other rotatably, and the rotation control member is interposed between an inner periphery surface of the outer case and an outer periphery surface of the inner case on an outer periphery side of the damper body.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a rotary damper used in a vehicle such as an automobile.

[0003] 2. Description of the Prior Art

[0004] In a vehicle such as an automobile there are provided various receptacle portions within a passenger compartment. Some such receptacle portions are provided with a lid which closes when it is pushed once and opens when it is pushed once more.

[0005] Such a lid or the like is supported through a rotary damper as disclosed in Japanese Patent No. 2544628.

[0006] As shown in FIGS. 7 and 8, this rotary damper comprises a cylindrical rotor 1 which receives a rotational input, a housing 2 having a shaft 3 which is fitted in an inner periphery of the cylindrical rotor 1 and also having a cylindrical wall which surrounds the shaft 3, a viscous fluid 5 interposed between the inner periphery of the cylindrical rotor 1 and the shaft 3 of the housing 2, a coiled spring 6 interposed between an inner periphery of the cylindrical wall 4 of the housing 2 and an outer periphery of the cylindrical rotor 1, the coiled spring 6 being fixed at one end thereof to the housing 2 and at an opposite end thereof to the cylindrical rotor 1 and being tightened with rotation of the cylindrical rotor 1 which rotation is performed upon receipt of a rotational input in the cylindrical rotor, a cover 7 which is fixed to the housing 2 so as to close an open end face of the cylindrical wall 4 of the housing and whose inner surface is opposed to an end face of the cylindrical rotor 1, a spiral groove 9 formed in one of the inner surface of the cover 7 and the end face of the cylindrical rotor 1 and provided at one end thereof with a heart cam groove 10, and an operating pin 8 mounted to the other of the cover 7 and the cylindrical rotor 1 and guided through the spiral groove 9.

[0007] An input/output shaft 12 which projects outward from the cover 7 is integral with the cylindrical rotor 1, and a lid of a receptacle portion is attached to the input/output shaft 12.

[0008] The heart cam groove 10 is provided with a heart island 10′, end portions 10 a and 10 c of two arcuate and straight paths respectively formed along both side portions of the heart island 10′, and a slit 10 b formed in a rear end portion of the heart island 10′ at an intermediate position of a path which interconnects the arcuate and straight paths at positions near the two end portions 10 a and 10 c.

[0009] When the lid is pushed into a closed state from an open state, the input/output shaft 12 connected to the lid is rotated. Thus, when the lid is pushed, a rotational force is imparted to the cylindrical rotor 1 through the input/output shaft 12, whereby the coiled spring 6 is tightened and a restoring force is accumulated in the spring.

[0010] At this time, the operating pin 8 moves along the spiral groove 9 to one end side from an opposite end 9′ side of the same groove, further moves to the heart cam groove 10 formed on one end side of the spiral groove 9, then reaches one end portion 10 a of the heart cam groove 10 through the arcuate path of the same groove, thereafter returns slightly and is caught in the slit 10 b of the heart island 10′, so stops, whereby the lid is kept closed.

[0011] When the lid is pushed again, the operating pin 8 is disengaged from the slit 10 b formed in the heart island 10′ and moves to the other end portion 10 c of the heart cam groove 10, then with the restoring force of the coiled spring 6, returns from the other end portion 10 c of the heart cam groove 10 to one end side of the spiral groove 9 through the straight path, and thereafter moves to the opposite end 9′ side of the spiral groove 9, whereby the lid opens.

[0012] In such a conventional rotary damper, however, since the operating pin 8 is provided on the cover 7 side of the cylindrical rotor 1, a vertical size of the entire device becomes large beyond a compact size. Besides, since the device is constituted using the cylindrical rotor 1, housing 2 and cover 7, the number of components used is large and hence the cost is high.

SUMMARY OF THE INVENTION

[0013] To solve the above-mentioned problems, it is an object of the present invention to provide a rotary damper comprising a damper body mounted on a rotary shaft, a cam mechanism provided in the damper body to set a rotation pattern of the rotary shaft, a restoring force accumulating member which accumulates a restoring force in accordance with rotation of the rotary shaft, and a rotation control member for controlling the rotation of the rotary shaft, wherein the damper body is formed by setting a bottomed, cylindrical outer case having an opening at one end thereof and a bottomed, cylindrical inner case having an opening at one end thereof face to face with each other and fitting the two with each other rotatable, and the rotation control member is interposed between an inner periphery surface of the outer case and an outer periphery surface of the inner case on an outer periphery side of the damper body, thereby attaining a compact structure and reduction in the number of components used and consequent reduction of cost.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 illustrates the whole of an embodiment of the present invention;

[0015]FIG. 2 is a partial enlarged diagram of FIG. 1;

[0016]FIG. 3 is an exploded perspective view of a rotary damper shown in FIG. 2;

[0017]FIG. 4 is an end view of an outer case as seen from an opening side thereof;

[0018]FIG. 5 is a partial enlarged sectional view of the outer case shown in FIG. 4;

[0019]FIG. 6 is an end view of an inner case as seen from an opening side thereof;

[0020]FIG. 7 illustrates a conventional rotary damper; and

[0021]FIG. 8 is an explanatory diagram of a heart cam groove shown in FIG. 7.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0022] An embodiment of the present invention will be described hereinunder with reference to the accompanying drawings.

[0023] First, a description will be given about construction. Within a passenger compartment of a vehicle such as an automobile, a receptacle portion 26 such as a drink holder 25 is provided for example in such a portion as a center console or an instrument panel, as shown in FIG. 1. The drink holder 25 is constructed so as to be covered with an opening/closing lid 27 which closes when pushed once and opens when pushed once more. In FIG. 1, the reference numeral 28 denotes a drink container such as a drink can or a PET bottle.

[0024] The lid 27 is journaled at one end thereof to a structural member 30 such as a center console or an instrument panel through a semi-shaft member 29 such as a clip pin and is supported at an opposite end thereof by the structural member 30 through an input/output shaft 31 (rotary shaft) and a rotary damper 32 in this embodiment.

[0025] As shown in FIGS. 2 to 6, the rotary damper 32 of this embodiment is provided with a bottomed, short cylindrical, outer case 35 having an opening at one end thereof and a bottomed, short cylindrical, inner case 37 formed a size smaller than the outer case 35 and having an opening at one end thereof.

[0026] The outer case 35 and the inner case 37 are brought into face to face with each other and the inner case 37 is rotatably fitted in the interior of the outer case 35, whereby a generally short cylindrical damper body 38 can be formed. An outer surface of a bottom 35 a of the outer case 35 in the damper body 38 is fixed to the structural member 30. On an inner surface of the bottom 35 a of the outer case 35 is formed a rib 39 which extends in the circumferential direction to effect positioning of a front-end inner periphery of a peripheral wall 37 b of the inner case 37.

[0027] Between the outer case 35 and the inner case 37 is provided a retaining portion 40 for making both cases rotatable in the mutually fitted state and for retaining them in the axial direction. For example, the retaining portion 40 comprises plural (four in the figures) retaining pawls 41 arranged in the circumferential direction on a front end of a peripheral wall 35 b of the outer case 35 to retain an outer surface of a bottom 37 a of the inner case 37.

[0028] On an outer periphery side of the damper body 38, a viscous fluid 42, e.g., silicone grease, is interposed between an inner periphery surface of the peripheral wall 35 b of the outer case 35 and an outer periphery surface of the peripheral wall 37 b of the inner case 37, the viscous fluid 42 being used as a resistor acting as a rotation control member. In order to seal the viscous fluid 42, a pair of O-rings 43 and 44 are interposed between the inner periphery surface of the outer case 35 and the outer periphery surface of the inner case 37 so as to be spaced a predetermined distance from each other. In this case, one O-ring 43 is fitted and compressed between a base portion of an inner periphery of the peripheral wall 35 b of the outer case 35 and a circumferentially extending stepped portion formed at a front-end outer periphery surface of the peripheral wall 37 b of the inner case 37. Likewise, the other O-ring 44 is fitted and compressed between a flange 45 formed on a rear-end outer periphery surface of the peripheral wall 37 b of the inner case 37 and a circumferentially extending stepped portion formed on a front-end inner periphery surface of the peripheral wall 35 a of the outer case 35. The flange 45 is flush with the bottom 37 a of the inner case 37.

[0029] On the other hand axial holes 46 and 47 for passing therethrough of the external input/output shaft 31 are formed axially of the outer case 35 and the inner case 37, respectively. In the interior of the inner case 37, a cylindrical shaft holding portion 48 is projectingly provided to hold the input/output shaft 31 which is inserted in an axial position into the damper body 38. Key lugs 50 are formed on a front-end inner periphery side of the shaft holding portion 48 to fit in axially extending key ways 49 formed in a front-end outer periphery of the input/output shaft 31. A front-end outer periphery of the shaft holding portion 48 is formed with a stepped portion, which stepped portion is engaged with a stepped portion formed on an inner surface side of the axial hole 46 in the outer case 35 to effect positioning of the two. An intermediate portion of the input/output shaft 31 is supported by the structural member 30 through a bearing member 51 such as a bushing, and a rear end portion thereof is formed with a lid mounting portion 52 for mounting the lid 27 and a flange 53.

[0030] A coiled spring 55 as a restoring force accumulating member is fitted on the outer periphery of the shaft holding portion 48. One end of the coiled spring 55 is anchored to a retaining hole 57 formed in the bottom 37 a of the inner case 37, while an opposite end of the coiled spring 55 is anchored to a retaining portion 56 formed on the rib 39 which is formed on the inner periphery of the bottom 35 a of the outer case 35.

[0031] Further, a generally arcuate guide groove 61 having a heart cam groove 60 at one end is formed as part of a cam mechanism in either the inner case 37 or the outer case 35 (the inner case 37 in FIGS. 2 and 6) located in the interior of the damper body 38.

[0032] The heart cam groove 60 comprises a heart island 62, end portions 60 a and 60 b of two arcuate and straight paths respectively which are formed along both side portions of the heart island 62, and a slit 60 c formed in a rear end portion of the heart island 62 at an intermediate position of a path which interconnects the two end portions.

[0033] In the interior space of the damper body 38 and sideways of the coiled spring 55 there is disposed an operating pin 64 as part of the cam mechanism, the operating pin 64 being guided at one end thereof by both heart cam groove 60 and guide groove 61 and retained at an opposite end thereof by a pin retaining portion 63 provided in the other (the outer case 35 in FIGS. 2 and 4) of the inner and outer cases 37, 35. In the other (the outer case 35 in FIGS. 3, 4 and 5) of the inner and outer cases 37, 35 there is provided a guide portion 65 which restricts a movement range of the operating pin 64 and which guides and holds an intermediate part of the operating pin 64 to prevent the pin from coming off the heart cam groove 60, guide groove 61 and pin retaining portion 63.

[0034] The following description is now provided about the operation of this embodiment.

[0035] The rotary damper 32 functions so that the lid 27 of the drink holder 25 closes when pushed once and opens when pushed once more.

[0036] More specifically, when the lid 27 is pushed into a closed state from an open state, the input/output shaft 31 connected to the lid 27 is rotated and the inner case 37, which is rendered integral in the rotational direction with the input/output shaft 31 through the key ways 49 and the key lugs 50, rotates relative to the outer case 35.

[0037] At this time, the viscous fluid 42 such as silicone oil interposed between the inner periphery surface of the outer case 35 and the outer periphery surface of the inner case 37 functions as fluid bearing. When the rotational force is thus imparted to the inner case through the lid 27, the coiled spring 55 is tightened, whereby a restoring force is accumulated.

[0038] At this time, the operating pin 64 moves along the guide groove 61 from an opposite end side to one end side of the guide groove, then shifts to the heart cam groove 60 located at one end side of the guide groove and reaches one end portion 60 a of the heart cam groove 60 through the arcuate path of the same groove, thereafter returns a little and is caught in the slit 60 c of the heart island 62, so stop, whereby the lid 27 is kept closed.

[0039] Next, when the lid 27 is pushed again, the operating pin 64 shifts from the slit 60 c of the heart island 62 to the other end portion 60 b of the heart cam groove 60, then with the restoring force of the coiled spring 55 the operating pin 64 returns from the other end portion 60 b of the heart cam groove 60 to one end side of the guide groove 61 through the straight path, thereafter moves to the opposite end side of the guide groove 61, whereby the lid 27 opens automatically.

[0040] At this time, the viscous fluid 42 as a resistor such as silicone oil interposed between the inner periphery surface of the outer case 35 and the outer periphery surface of the inner case 37 functions as a rotation control member, so that the lid 27 opens slowly with a high-class feeling.

[0041] Thus, according to this embodiment, since bottomed, short cylindrical outer and inner cases 35, 37 each having an opening at one end thereof are brought into face to face with each other and are fitted together to form the damper body 38, it is possible to reduce the number of components used and hence possible to reduce the cost.

[0042] Further, since the operating pin 64 is disposed sideways of the coiled spring 55 in the internal space of the damper body 38, it is possible to form the damper body 38 in a generally short cylindrical shape and thereby attain a compact structure of the device.

[0043] Although an embodiment of the present invention has been described above in detail with reference to the accompanying drawings, no limitation is made thereto, but there may be made design changes and the like insofar as they are within the scope not departing from the gist of the present invention.

[0044] For example, it is not limited to the lid 27 of the drink holder that the rotary damper 32 of this embodiment is applied. 

What is claimed is:
 1. A rotary damper comprising: a damper body mounted on a rotary shaft; a cam mechanism provided in the damper body to set a rotation pattern of the rotary shaft; a restoring force-accumulating member which accumulates a restoring force in accordance with rotation of the rotary shaft; and a rotation control member for controlling the rotation of the rotary shaft, wherein said damper body is formed by setting a bottomed, cylindrical outer case having an opening at one end thereof and a bottomed, cylindrical inner case having an opening at one end thereof face to face with each other and fitting the two with each other rotatably, and said rotation control member is interposed between an inner periphery surface of said outer case and an outer periphery surface of said inner case on an outer periphery side of said damper body.
 2. A rotary damper according to claim 1, wherein it further comprises a shaft holding portion formed in the interior of said inner case for coupling a rotational axis of said damper body and an external rotary shaft, and a coiled spring as a restoring force accumulating member, fitted on an outer periphery side of said shaft holding portion, both ends of said coiled spring being anchored to said inner case and said outer case, respectively, wherein said cam mechanism comprises a guide groove and an operating pin, said guide groove being formed in one of said inner case and said outer case and having a heart cam groove in an end portion thereof, said operating pin being guided at one end thereof by said guide groove and retained at an opposite end thereof by the other of said inner case and said outer case; and said cam mechanism is disposed sideways of said coiled spring in an interior space of said damper body.
 3. A rotary damper according to claim 1, wherein said rotation control member is a viscous fluid.
 4. A rotary damper according to claim 3, wherein said viscous fluid comprises silicon grease. 